CVE-2025-63951 identifies an insecure deserialization vulnerability in the rss-mp3.php script of the MiczFlor RPi-Jukebox-RFID project, specifically introduced in commit 4b2334f0ae0e87c0568876fc41c48c38aa9a7014 dated 2025-10-07. The vulnerability stems from the direct use of the 'rss' GET parameter data as input to PHP's unserialize() function without any validation or sanitization. This allows a remote attacker to craft malicious serialized PHP objects and inject them via the 'rss' parameter. When the application unserializes this data, it processes the attacker-controlled objects, which can cause unexpected behavior such as application errors or denial of service (DoS). The vulnerability does not impact confidentiality or integrity but severely affects availability by potentially crashing or destabilizing the application. Exploitation requires no authentication or user interaction and can be performed remotely over the network. The affected software is the MiczFlor RPi-Jukebox-RFID project, an open-source project designed for Raspberry Pi-based jukebox systems using RFID tags. No patches or fixes are currently linked, and no known exploits have been reported in the wild. The vulnerability is categorized under CWE-502 (Deserialization of Untrusted Data) and has a CVSS v3.1 base score of 7.5, reflecting high severity due to ease of exploitation and impact on availability.

For European organizations using the MiczFlor RPi-Jukebox-RFID project or similar embedded systems relying on PHP unserialize() without validation, this vulnerability poses a significant risk of denial of service. Disruption of these jukebox systems could impact environments where they are used for public or commercial audio services, such as retail, hospitality, or cultural institutions. While the vulnerability does not expose sensitive data or allow code execution, the loss of availability can degrade user experience and operational continuity. Additionally, if these systems are integrated into larger IoT or automation frameworks, the DoS could cascade, affecting broader operational technology environments. The lack of authentication and remote exploitability increases the risk profile, especially in network-exposed deployments. European organizations with limited patch management capabilities or those using customized versions of the software may face prolonged exposure. The impact is primarily operational but could have reputational consequences if service outages occur in customer-facing scenarios.

Immediate mitigation should focus on preventing untrusted data from reaching the unserialize() function. This can be achieved by implementing strict input validation and sanitization on the 'rss' GET parameter to ensure only expected, safe data formats are processed. If possible, replace the use of PHP's unserialize() with safer data parsing methods such as JSON decoding, which do not allow object injection. Network-level controls like web application firewalls (WAFs) can be configured to detect and block suspicious serialized payloads targeting the 'rss' parameter. Restricting access to the vulnerable script to trusted networks or authenticated users can reduce exposure. Monitoring application logs for unusual unserialize() errors or crashes can provide early detection of exploitation attempts. Organizations should track updates from the MiczFlor project for official patches and apply them promptly. For embedded devices, ensure secure firmware update mechanisms are in place to facilitate timely remediation. Finally, conducting security reviews of similar PHP deserialization usage in other projects can prevent analogous vulnerabilities.